Unpluggable bit



' Paltentiad Aug. 16, 1927.

UNITED STATE-S eiaonen ir. wem, 013 1101m emims, cuxronnm. v

UNIPLU'GGAIBLE BIT. 1

Appl1oa.tlon mm Ootober 27,192 mm m. 05,114.

This invention relates to improvements in v drill bits used in drilling'wells.

Most drill bits used in connection with rotary drilling outfits have discharge p a;ssages 5 forri1ed in their bodies through wh1ch c1rculafiion fluid is discharged during the dyilling operations. In lowering the bit 1nto the Well hole to oontiriue drilling, it freq uenbly occurs that the drill bit strikes the s1de of the hole and solid matter asses upwardly through the discharge passages and intothe drill pipe, tending to plug 1 1p the discharge pa'ssages, so that when the c1rculation mud pumps are applied, it is difllcult and lisometimes impossible to have the circulation fluid dischar ed. The same eife ct sometimes happens w en the drill bit is at the bottom of the hole and the pr6ssure applied by the circulation pum;ps is temporarily released, allowing the flu1d in the hole to flow up through the discharge assages and lI1t0 the d1ill pipe, carrying wit it solid ma ter1al which is apt to plug the discharge passages. An o'bject of this invention is to. provide a drill bit of imprwed construction wherei-n the upward flow of fluid through the dis- Charge passages in the bit is efl'ectively pre- Vei1ted 01 retarded in such a mz'mner that solids oannot pass upwamdly through the 'discharge passages.

With the foregoing and other objeotsirx view which will be made manifest in the following detailed. description and specifically pointed out in the appended claims, reference is had to the accompanying drawings for an illustrative embodiment of the invention, wherein:

Figure 1 is a side elev'ation of a drill bit of the improved construction,

F ig.2 is a vertioal section taken substantially on the line 2-2 of Fig. 1, and

Fi 3 is a horizontal seqt1on.taken upon the l1ne 3 3 of Fig. 2. 1

Referring to the accompanying drawings wherein similar reference 'characters designate similar Parts throughout, the bit on whichthe invention is illstrated as having been embodied is a, fish teil bit indicated at 10, although it will be readily understood that the invention is capable of being eplied to various other types of bits which ave disoharge passa'ges for the discharge of circulation fluid. As is conventional in this dass of bits, the drill bit is provided with a pin 11 threaded for attaachment to the drill pipe. In the pin'there is f01 med a, vertical hre 12 W.ith which bwo upwarclly convergent discharge passages 13 and 14 communicate. The above mentioned coustruction is conventional, and circulation fluid which is forced downwardly through the drill ipe enters the bore 12 and is dis charged t rough the downwardlydivergent discharge passages 13 and 14. The invention consists of forming tv'vo upwardly convergent bores 15 and 16 in the body of the bit which have their upper ends communicating wit-h the disohargepassages 13 and 14 respectively. The bores 15 and 16 are greater in diameter than the diameters of the discharge passages. Within eaoh of the bores 15 and 16 there is a hollow steel ball, such as is indicated at 17 and 18. These balls ha.ve diameters slightly smaller than the diameters of their respective bores 15 and 16 so that the are freel slidable therein. Thelower en of each 0 the bores is threaded to redeive tubular members 19 and 20, which preferabl have squared apertures therethrou;gh, so tllat they can be readily screwed into place upon the insertion of a, square object. The tubular members 19 and 20 serve to maintain the balls 17 and 18 in t-heir respective bores and adjacent the u'pper ends of the bores.

The operation of the improved drill bit is as follows: When there 1s any tendency for fluid toflow upwardly through tlle discharge passages 13 and 14, which may be created upoxi lowering the bit into the hole o1 stopping the circulati0n umps, fluid also tends to rise 01' flow upwardly through the tubular members and through the two bores, causing the gal1s 17 and 18 to rise within the bores and substantiall close the discharge passages 13 and 14. I the upper end-of each bare is so formed es to provide a. ood seat, the balls 17 and 18 act es check va vespreventing flow of fluid up through the disohar e passages and also the bores, so that no uid or solid material can enter the dri1l pipe or the bore 12. This onstruction wherem a good seat is provided is ve advanta eous when the bit is used in sha 10W dril ing. In this case the balls 17 and PATENT OFFICE.

18 not only prevent the solid material fr0m passing up through the bit andplugging it, bot also serVe as float valves for preventing enyfluid from ehtering the drill'pipe. In the case of de'ep drillii1g, however, 1t is disadvanta. eous to completelyl revent the entrance o liquids into the dr' pipe, be-

hause of the fact that the high press1ire ab Consequently, when the bit is used in deep drilling, it is highly desirable that the seat for the balls 17 and 18 be otherwise than a perfect seat, so that the ba1ls when in their seated positions will allow liquids to pass slowly through the discharge passages 13 and 14 and thus partially equalize the pressures on the inside and outside o'f the lower end of the drill pipe. At the samefime, however, the ba1ls 17 and 18 function as strainers, allowing the liquid t0 seep through but preventing any solid material from getting by which might plug the passages.

When it is desired to continue the drilling operations, the circulation pumps arg a ain started and upon the downward flow of uid within the drill pipe, the balls 17 and 18 drop to the bottom of their respective bores, assuming .positions on top of the tubular'mem bers 19 and 20, as indicated by dotted lines upon Fig 2. Because 0f the fact that the bores 15 and 16 are greater in diameter than the diameters of the passages 13 sind 14,there is no tendency or danger of the bal1s preventing downward flow of fluid through the passages. The tubular members 19 and 20 are preferably so arranged that the balls are maintained VGI'Y/Il8fll the passages 13 and 14, so that there is very little 01 no tendenc 0f solid material, such as sand or grit, eo lecting in the bores 15 and 16. on top of the balls, which might prevent the upward movement of the balls when there was an upward flow of fluid through the bit. When the balls are in their lowe r position it is not intended that they seat upon the.upper ends of the tubular members so as to close them. This will be efl'ectively prevented because of the fact that the apertures in the tubular members are square. Consequently, as there is seine clearance between the bal ls and the sides of their respective bores upon the downward flow of fluid, some fluid may escape past fche balls throu h the bores and obstructed. By reason of this factthe' apthrough the tubular mem ers, keeping the b0res clean. m

It will be noted that by the improved coustruction the discharge passages 13 and 14:v

remain straight and that when there is a downward flow of fluid through the drill bit, these passages are entirely or complete un-' p lication of the inVention to a, drill bit is Such thait there is no material increasebf Premure. required to be exerted bythe Circuation pumpg to discharge the circulation fiuid through the bit.

' It is" understoo'd-that various changes ina y i,ese,oers

I claim:

l. A drill bit having a, straight discharge assage therethrou h for the discharge of circulation fluid, t ere bei.ng a cavity arran ed in the bit communicating with said disc arge passage, and a closure receivable wh0lly within suid cavity capable of moving into-said discharge assage so as to prevent or retard upward ow therethrough.

2. A drill bit having a discharge assage formed in its body, a bore communicating with said pas sage, a balldisposed within said boria adapted to close said assage so as t0 prevent o'r retard upward ow therethrough, and means for maintaining said ball within'said bore, 4

3. A drill bit havifig a discharge passag'e formed in its body, a bore communicating with said passage, a ball disposed within said bore adapted to close said passage so as to prevent or retard upward flow therethrough, and means for' ma'mtaining said ball within said bore, said ball and bore being of a greater diameter than the diameter of said'passage.

4. A drill bit having a plurality of dissages, hollow balls isposed in auch of said bores adapted to'close said passages so as toprevent o1 retard the upward flow of fluid therethrough, and means for maintaining said balls within their respective bores.

5. A drill bit having a plurality of discharge passages formed in its body and bores communioatin with each of said passages, hollow ba1ls isposed in each of said b0res adapted to cl ose said passages so as to revent or retard the upward flow of uid therethrough, and miaans for maintaining said balls within their respective bores', said balls and bores being of greater diameters than the diameters of the passages with which they are associated.

6. A drill bit havin two downwardly divergent straight ischarge passages forme in its body through which circulation flui is adapted to be dis'charged, there bein to bores formed in said body, each of. w ic communicates withone of said discha'r passages, auch bore being of a greater diaeter than the diameter of the discharge gassage with which it is associated, a hollow all disposedw'ithin nach bore which is greater' in diameter than the diameter of the passagb with Which it is associated and which is aidapted t'o c losethe assage so a3 to prevent or retard the u war' flow of fluid @herethrough and a tub ar member threaded into the lower end of each bare for main taining the ball therein.

7. A drill bit having two downwardly divergent straight discharge passages formed in its body through which circulation fluid is adapted to' be d1scharged'thre being two bdres formd in said body, each bf which communicates with one of sa.id discharge eater diampassages, each bore being of a eter than the diameter of the d1s char%:a assag'e with which it is associated, a 010W a plurality of d1scharge passages formed m 1 its body, of means form1ng strainers in said% assages which function r0m assing upwardl sages, ut permit 1iqui therethrough.

to frevnt solids through the" pasto Pass upwardly 20 9. Thq combinatiofi ivitlia drill'bifi having a plural1ty o f discharge passages formed in its body, of means forming strainers in said gassages which function 1 0m passing upwardly sages, but permit liquids therethrough, said means as to leave the unobstrcted when of fluid therethrogh,

to preventsolids through the pasto pass upwardly being so arranged discharge passages completely there is a. do wuv?ard flow 30 In testimony whereof'l have sign ed m y name to this s'pecification.

EO THAGARD. 

